264 research outputs found
Dietary cholesterol promotes repair of demyelinated lesions in the adult brain
Multiple Sclerosis (MS) is an inflammatory demyelinating disorder in which remyelination failure contributes to persistent disability. Cholesterol is rate-limiting for myelin biogenesis in the developing CNS; however, whether cholesterol insufficiency contributes to remyelination failure in MS, is unclear. Here, we show the relationship between cholesterol, myelination and neurological parameters in mouse models of demyelination and remyelination. In the cuprizone model, acute disease reduces serum cholesterol levels that can be restored by dietary cholesterol. Concomitant with blood-brain barrier impairment, supplemented cholesterol directly supports oligodendrocyte precursor proliferation and differentiation, and restores the balance of growth factors, creating a permissive environment for repair. This leads to attenuated axon damage, enhanced remyelination and improved motor learning. Remarkably, in experimental autoimmune encephalomyelitis, cholesterol supplementation does not exacerbate disease expression. These findings emphasize the safety of dietary cholesterol in inflammatory diseases and point to a previously unrecognized role of cholesterol in promoting repair after demyelinating episodes
Anesthesia triggers drug delivery to experimental glioma in mice by hijacking caveolar transport
Abstract Background: Pharmaceutical intervention in the CNS is hampered by the shielding function of the blood-brain barrier (BBB). To induce clinical anesthesia, general anesthetics such as isoflurane readily penetrate the BBB. Here, we investigated whether isoflurane can be utilized for therapeutic drug delivery. Methods: Barrier function in primary endothelial cells was evaluated by transepithelial/transendothelial electrical resistance, and nanoscale STED and SRRF microscopy. In mice, BBB permeability was quantified by extravasation of several fluorescent tracers. Mouse models including the GL261 glioma model were evaluated by MRI, immunohistochemistry, electron microscopy, western blot, and expression analysis. Results: Isoflurane enhances BBB permeability in a time- and concentration-dependent manner. We demonstrate that, mechanistically, isoflurane disturbs the organization of membrane lipid nanodomains and triggers caveolar transport in brain endothelial cells. BBB tightness re-establishes directly after termination of anesthesia, providing a defined window for drug delivery. In a therapeutic glioblastoma trial in mice, simultaneous exposure to isoflurane and cytotoxic agent improves efficacy of chemotherapy. Conclusions: Combination therapy, involving isoflurane-mediated BBB permeation with drug administration has far-reaching therapeutic implications for CNS malignancies
Correlation of immune phenotype with IDH mutation in diffuse glioma.
Tumor infiltrating lymphocytes (TILs) and programmed death ligand 1 (PD-L1) are targets of immune checkpoint inhibitors.
Forty-three World Health Organization (WHO) grade II/III gliomas (39 IDH-mutant [mut], 4 IDH-wildtype [wt]) and 14 IDH-mut glioblastomas (GBM) were analyzed for TIL (CD3+; PD1+) infiltration and PD-L1 expression. Results were compared with the data of a previously published series of 117 IDH-wt glioblastomas. PD-L1 gene expression levels were evaluated in 677 diffuse gliomas grades II-IV from The Cancer Genome Atlas (TCGA) database.
TIL and PD-L1 expression were observed in approximately half of WHO grade II/III gliomas. IDH-wt status was associated with significantly higher TIL infiltration and PD-L1 expression among all (grades II-IV) cases (n = 174, P < 0.001) and within the cohort of glioblastomas (n = 131, P < 0.001). In low-grade glioma (LGG) and glioblastoma cohorts of TCGA, significantly higher PD-L1 gene expression levels were evident in IDH-wt compared with IDH-mut samples (LGG: N = 516; P = 1.933e-11, GBM: N = 161; P < 0.009). Lower PD-L1 gene expression was associated with increased promoter methylation (Spearman correlation coefficient -0.36; P < 0.01) in the LGG cohort of TCGA. IDH-mut gliomas had higher PD-L1 gene promoter methylation levels than IDH-wt gliomas (P < 0.01).
The immunological tumor microenvironment of diffuse gliomas differs in association with IDH mutation status. IDH-wt gliomas display a more prominent TIL infiltration and higher PD-L1 expression than IDH-mut cases. Mechanistically this may be at least in part due to differential PD-L1 gene promoter methylation levels. Our findings may be relevant for immune modulatory treatment strategies in glioma patients
Managerial power in the German model: the case of Bertelsmann and the antecedents of neoliberalism
Our article extends the research on authoritarian neoliberalism to Germany, through a history of the Bertelsmann media corporation – sponsor and namesake of Germany’s most influential neoliberal think-tank. Our article makes three conceptual moves. Firstly, we argue that conceptualizing German neoliberalism in terms of an ‘ordoliberal paradigm’ is of limited use in explaining the rise and fall of Germany’s distinctive socio-economic model (Modell Deutschland). Instead, we locate the origins of authoritarian tendencies in the corporate power exercised by managers rather than in the power of state-backed markets imagined by ordoliberals. Secondly, we focus on the managerial innovations of Bertelsmann as a key actor enmeshed with Modell Deutschland. We show that the adaptation of business management practices of an endogenous ‘Cologne School’ empowered Bertelsmann’s postwar managers to overcome existential crises and financial constraints despite being excluded from Germany’s corporate support network. Thirdly, we argue that their further development in the 1970s also enabled Bertelsmann to curtail and circumvent the forms of labour representation associated with Modell Deutschland. Inspired by cybernetic management theories that it used to limit and control rather than revive market competition among its workforce, Bertelsmann began to act and think outside the postwar settlement between capital and labour before the settlement’s hotly-debated demise since the 1990s
Theory and simulation of quantum photovoltaic devices based on the non-equilibrium Green's function formalism
This article reviews the application of the non-equilibrium Green's function
formalism to the simulation of novel photovoltaic devices utilizing quantum
confinement effects in low dimensional absorber structures. It covers
well-known aspects of the fundamental NEGF theory for a system of interacting
electrons, photons and phonons with relevance for the simulation of
optoelectronic devices and introduces at the same time new approaches to the
theoretical description of the elementary processes of photovoltaic device
operation, such as photogeneration via coherent excitonic absorption,
phonon-mediated indirect optical transitions or non-radiative recombination via
defect states. While the description of the theoretical framework is kept as
general as possible, two specific prototypical quantum photovoltaic devices, a
single quantum well photodiode and a silicon-oxide based superlattice absorber,
are used to illustrated the kind of unique insight that numerical simulations
based on the theory are able to provide.Comment: 20 pages, 10 figures; invited review pape
Integrated Molecular-Morphologic Meningioma Classification: A Multicenter Retrospective Analysis, Retrospectively and Prospectively Validated
PURPOSE: Meningiomas are the most frequent primary intracranial tumors. Patient outcome varies widely from benign to highly aggressive, ultimately fatal courses. Reliable identification of risk of progression for individual patients is of pivotal importance. However, only biomarkers for highly aggressive tumors are established (CDKN2A/B and TERT), whereas no molecularly based stratification exists for the broad spectrum of patients with low- and intermediate-risk meningioma. METHODS: DNA methylation data and copy-number information were generated for 3,031 meningiomas (2,868 patients), and mutation data for 858 samples. DNA methylation subgroups, copy-number variations (CNVs), mutations, and WHO grading were analyzed. Prediction power for outcome was assessed in a retrospective cohort of 514 patients, validated on a retrospective cohort of 184, and on a prospective cohort of 287 multicenter cases. RESULTS: Both CNV- and methylation family-based subgrouping independently resulted in increased prediction accuracy of risk of recurrence compared with the WHO classification (c-indexes WHO 2016, CNV, and methylation family 0.699, 0.706, and 0.721, respectively). Merging all risk stratification approaches into an integrated molecular-morphologic score resulted in further substantial increase in accuracy (c-index 0.744). This integrated score consistently provided superior accuracy in all three cohorts, significantly outperforming WHO grading (c-index difference P = .005). Besides the overall stratification advantage, the integrated score separates more precisely for risk of progression at the diagnostically challenging interface of WHO grade 1 and grade 2 tumors (hazard ratio 4.34 [2.48-7.57] and 3.34 [1.28-8.72] retrospective and prospective validation cohorts, respectively). CONCLUSION: Merging these layers of histologic and molecular data into an integrated, three-tiered score significantly improves the precision in meningioma stratification. Implementation into diagnostic routine informs clinical decision making for patients with meningioma on the basis of robust outcome prediction
Targeted Gene Expression Profiling Predicts Meningioma Outcomes and Radiotherapy Responses
Surgery is the mainstay of treatment for meningioma, the most common primary intracranial tumor, but improvements in meningioma risk stratification are needed and indications for postoperative radiotherapy are controversial. Here we develop a targeted gene expression biomarker that predicts meningioma outcomes and radiotherapy responses. Using a discovery cohort of 173 meningiomas, we developed a 34-gene expression risk score and performed clinical and analytical validation of this biomarker on independent meningiomas from 12 institutions across 3 continents (N = 1,856), including 103 meningiomas from a prospective clinical trial. The gene expression biomarker improved discrimination of outcomes compared with all other systems tested (N = 9) in the clinical validation cohort for local recurrence (5-year area under the curve (AUC) 0.81) and overall survival (5-year AUC 0.80). The increase in AUC compared with the standard of care, World Health Organization 2021 grade, was 0.11 for local recurrence (95% confidence interval 0.07 to 0.17, P \u3c 0.001). The gene expression biomarker identified meningiomas benefiting from postoperative radiotherapy (hazard ratio 0.54, 95% confidence interval 0.37 to 0.78, P = 0.0001) and suggested postoperative management could be refined for 29.8% of patients. In sum, our results identify a targeted gene expression biomarker that improves discrimination of meningioma outcomes, including prediction of postoperative radiotherapy responses
The relationship between doses of mindfulness-based programs and depression, anxiety, stress, and mindfulness: a dose-response meta-regression of randomized controlled trials
Abstract
Objectives: Research with mindfulness-based programs (MBPs) has found participating in an MBP to predict beneficial outcomes, however, there is currently mixed research regarding the most helpful dose. This review aimed to determine whether different doses related to MBPs significantly predict outcomes.
Methods: Systematic literature searches of electronic databases and trial registration sites for all randomized controlled trials of MBPs identified 203 studies (N=15,971). Depression was the primary outcome at post-program and follow-up, with secondary outcomes being mindfulness, anxiety and stress. Doses examined related to session numbers, duration and length, facilitator contact and practice. Dose-response relationships were analyzed using meta-regression in R with separate analyses for inactive and active controls.
Results: Initial meta-analyses found significant between-group differences favoring MBPs for all outcomes. Meta-regression results suggested significant dose-response relationships for the mindfulness outcome for doses relating to face-to-face contact (d=0.211; C.I.[0.064,0.358]), program intensity (d=0.895; C.I.[0.315,1.474]) and actual program use (d=0.013; C.I.[0.001,0.024]). The majority of results for psychological outcomes, including depression, were not significant.
Conclusions:
This meta-regression examines dose-response relationships for different types and doses relating to MBPs. Considered together, MBPs appeared helpful compared to controls, supporting previous research. Based on meta-regression results, there was no evidence that larger doses are more helpful than smaller doses for predicting psychological outcomes; a finding consistent with some previous research particularly with non-clinical populations. Additionally, greater contact, intensity and actual use of MBPs predicting increased mindfulness corresponds with previous research and theory. Potential limitations and recommendations for future research are explored
Low fingertip temperature rebound measured by digital thermal monitoring strongly correlates with the presence and extent of coronary artery disease diagnosed by 64-slice multi-detector computed tomography
Previous studies showed strong correlations between low fingertip temperature rebound measured by digital thermal monitoring (DTM) during a 5 min arm-cuff induced reactive hyperemia and both the Framingham Risk Score (FRS), and coronary artery calcification (CAC) in asymptomatic populations. This study evaluates the correlation between DTM and coronary artery disease (CAD) measured by CT angiography (CTA) in symptomatic patients. It also investigates the correlation between CTA and a new index of neurovascular reactivity measured by DTM. 129 patients, age 63 ± 9 years, 68% male, underwent DTM, CAC and CTA. Adjusted DTM indices in the occluded arm were calculated: temperature rebound: aTR and area under the temperature curve aTMP-AUC. DTM neurovascular reactivity (NVR) index was measured based on increased fingertip temperature in the non-occluded arm. Obstructive CAD was defined as ≥50% luminal stenosis, and normal as no stenosis and CAC = 0. Baseline fingertip temperature was not different across the groups. However, all DTM indices of vascular and neurovascular reactivity significantly decreased from normal to non-obstructive to obstructive CAD [(aTR 1.77 ± 1.18 to 1.24 ± 1.14 to 0.94 ± 0.92) (P = 0.009), (aTMP-AUC: 355.6 ± 242.4 to 277.4 ± 182.4 to 184.4 ± 171.2) (P = 0.001), (NVR: 161.5 ± 147.4 to 77.6 ± 88.2 to 48.8 ± 63.8) (P = 0.015)]. After adjusting for risk factors, the odds ratio for obstructive CAD compared to normal in the lowest versus two upper tertiles of FRS, aTR, aTMP-AUC, and NVR were 2.41 (1.02–5.93), P = 0.05, 8.67 (2.6–9.4), P = 0.001, 11.62 (5.1–28.7), P = 0.001, and 3.58 (1.09–11.69), P = 0.01, respectively. DTM indices and FRS combined resulted in a ROC curve area of 0.88 for the prediction of obstructive CAD. In patients suspected of CAD, low fingertip temperature rebound measured by DTM significantly predicted CTA-diagnosed obstructive disease
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